Ian In 1917, Albert Einstein published the first paper acknowledging the science behind lasers. After decades of research and development, Theodore Maiman demonstrated the first functional laser in the Hughes Research Laboratory in 1960. By 1967, lasers were used to drill and cut metal in diamond molds. The advantages provided by laser power make its use in modern manufacturing widespread.
Laser is used to cut a variety of materials other than metal, and laser cutting has become an important part of modern sheet metal workshops. Before this technology was readily available, most workshops relied on shearing and stamping to manufacture workpieces from flat materials.
There are many styles of scissors, but they all perform a single linear cut and require multiple settings to create parts. When curved shapes or holes are required, shearing is not an option.
When shears cannot be used, punching is the preferred operation. Standard punches have various circular and linear shapes. When the required shape is non-standard, special shapes can be made. For complex shapes, CNC turret punch presses will be used. Several different types of punches are installed on the turret, which can provide the required shape when combined in sequence.
Unlike cutting, a laser cutting machine can generate any desired shape in one setup. Programming a modern laser cutting machine is only slightly more difficult than using a printer. The laser cutting machine does not require special tools, such as special punches. Eliminating special tools can reduce delivery time, inventory, development costs, and the risk of obsolete tools. Laser cutting also eliminates the costs associated with sharpening and replacing punches and maintaining the cutting edges of the shears.
Unlike shearing and stamping, laser cutting is also a non-contact activity. The force generated in the process of shearing and stamping will cause burrs and deformation of the parts, and secondary processing must be carried out. Laser cutting does not exert any force on the raw material, and many times laser-cut parts do not need to be deburred.
Other flexible thermal cutting methods such as plasma and flame cutting are also available, and they are generally cheaper than laser cutting machines. However, in all thermal cutting operations, there is a heat-affected zone, or HAZ, in which the chemical and mechanical properties of the metal change. HAZ weakens the material and causes problems in other operations (such as welding). Compared with other thermal cutting technologies, the heat-affected zone of laser-cut parts is very small, which reduces or eliminates the secondary processing required to process them.
The laser is not only suitable for cutting, but also for joining. Compared with more traditional welding processes, laser welding has many advantages.
Like cutting, welding produces HAZ. When welding on key components such as gas turbines or aerospace components, the size, shape, and characteristics must be controlled. Like laser cutting, the heat-affected zone of laser welding is very small, which has obvious advantages compared with other welding technologies.
Tungsten inert gas or TIG welding, the closest competitor to laser welding, uses tungsten electrodes to generate an arc to melt the metal being welded. The extreme conditions around the arc can cause tungsten to deteriorate over time, resulting in changes in welding quality. Laser welding is not affected by electrode wear, so the welding quality is more consistent and easier to control. Laser welding is the first choice for critical components and difficult-to-weld materials because the process is robust and repeatable.
The industrial use of lasers is not limited to cutting and welding. Lasers are used to manufacture very small parts with a geometric size of only a few microns. Laser ablation is used to remove rust, paint and other things on the surface of the part and prepare the part for painting. The use of laser marking is environmentally friendly (no chemicals), fast and permanent. Laser technology is very versatile.
Everything comes at a price, and lasers are no exception. Compared with other processes, industrial laser applications can be very expensive. Although not as good as a laser cutter, a high-definition plasma cutter can create the same shape and provide a clean edge with a smaller heat-affected zone at a small cost. Access to laser welding is also more expensive than other automatic welding systems. A complete laser welding system can easily exceed $1 million.
Like all industries, it is difficult to attract and retain skilled artisans. Finding qualified TIG welders is a challenge. It is also difficult to find welding engineers with laser experience, and it is almost impossible to find qualified laser welders. Both experienced engineers and welders need to develop robust welding operations.
Maintenance can also be very expensive. Laser power generation and transmission require complex electronics and optics. It is not easy to find someone who can troubleshoot the laser system. This is usually not a skill that can be found in the local trade school, so the service may require a visit by a technician from the manufacturer. The technicians of OEMs are very busy, and long delivery times are common problems that affect production plans.
Although industrial laser applications can be expensive, the cost of ownership will continue to increase. The number of small, inexpensive desktop laser engraving machines and DIY plans for laser cutting machines indicate that the cost of ownership is declining.
The laser power is clean, precise and versatile. Even considering these shortcomings, it is easy to understand why we will continue to see new industrial applications.
Christopher Tate is the director of facility operations at EthosEnergy in Houston.
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